Because of cost-effectiveness, speed and ease of application, as well as thoroughness of coverage in both open and confined areas, the practice of using pneumatically delivered or "blown" fibrous insulation materials, e.g., fiberglass, has become an increasingly popular method by which to install insulation in new and existing building constructions. The essential components of a typical blown fiberglass delivery system include a source of fiberglass material, conduit means for conveying the glass fibers from the fiberglass source to the installation site and a source of pressurized air such as a compressor, blower or the like, for generating a flow of pressurized air for entraining the fiberglass and delivering it from the fiberglass source through the conduit means for discharge at the installation site.
In order to promote efficient use of energy required to heat and/or cool new buildings, many building codes require that new buildings be constructed to provide a certain minimum resistance to heat flow. To achieve this threshold, insulation is typically installed between one or more of the buildings interior and exterior walls and possibly in superstructure and foundation areas such as crawl spaces, attics and basements. "R-value" refers to an insulation's thermal resistance or resistance to heat flow. The higher an insulation's R-value, the greater its thermal insulation capability. Existing building constructions can increase the R-value of their insulation by supplementing existing insulation with additional insulation.
The most influential factors for achieving a desired R-value when installing blown or pneumatically delivered fibrous installation are the thickness and density of the material to be installed. In "open" areas such as attics, for example, insulation thickness or density is not normally of great concern. However, in confined areas such as the voids between interior and building walls the available insulation space may be quite limited. This physical constraint restricts installation of blown insulation beyond a certain thickness and thus may materially impact the available R-value for insulation present in such areas.